Pyemotes herfsi

Taxobox
name = "Pyemotes herfsi"


image_width = 200px
image_caption =
regnum = Animalia
phylum = Arthropoda
classis = Arachnida
ordo = Acari
familia = Pyemotidae
genus = "Pyemotes"
species = "P. herfsi"
binomial = "Pyemotes herfsi"
binomial_authority = (Oudemans, 1936)

"Pyemotes herfsi", also known as the oak leaf gall mite or itch mite, is an ectoparasitic mite, identified in central Europe in 1936, whose presence in the United States was confirmed during the 1990s. Their bites often cause red, itchy, and painful wheals (welts). The mites are barely visible, measuring about 0.2 millimeters; their great reproductive potential, small size, and high capacity for dispersal by wind make them difficult to control or avoid. [ [http://www.srs.fs.usda.gov/pubs/23106 USDA, 2006] ] The United States Centers for Disease Control estimated that during an outbreak in August 2004, 54% of the population of Crawford County, Kansas, or about 19,000 people, suffered from its bites. [ [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5438a3.htm Centers for Disease Control, September 30, 2005] ] Other states in the US where humans have been affected during the 2000s are Nebraska, Oklahoma, Missouri, Texas, [ [http://ianrnews.unl.edu/static/0505021.shtml University of Nebraska, May 2, 2005] ] and Illinois. [ [http://www.chicagotribune.com/news/local/chicago/chi-bugbitesaug14,0,2767759.story?coll=chi-news-hed Chicago Tribune, August 14, 2007] ] Currently in August of 2008 an outbreak is being reported in the northern suburbs of Cincinnati, Ohio by the Hamilton County Public Health Department. [ [http://www.wlwt.com/health/17299642/detail.html?rss=cin&psp=news WLWT TV, Cincinnati, Ohio, August 26, 2008] ]

Life cycle

The mites' reported hosts have included "Anobium punctatum", the pink bollworm, "Grapholita molesta", "Tineola bisselliella" and various pests of stored grain, as well as humans and their pets. [ [http://www.bioone.org/perlserv/?request=get-document&doi=10.1603%2F0022-2585(2006)43%5B610%3APHAPAM%5D2.0.CO%3B2 BioOne.org] ] Their usual hosts in the United States are oak midge larvae. [ [http://www.bioone.org/perlserv/?request=get-document&doi=10.1603%2F0022-2585(2006)43%5B610%3APHAPAM%5D2.0.CO%3B2 BioOne.org] ] Newly emerged and mated females inject a neurotoxin-containing saliva into their hosts, which paralyzes the host and enables the pregnant female mites to feed on the host's hemolymph. A single mite can paralyze and kill an insect larva 166,000 times its own weight; within a few days, up to 250 adult mites emerge from the female. A life cycle can be completed within seven days. [ [http://www.srs.fs.usda.gov/pubs/ja/ja_moser050.pdf USDA 2006] ] Conditions that are cooler and moister than average favor its population growth. Outbreaks of attacks on humans in the United States have been attributed to fluctuations in the supply of oak midge larvae.

Distribution

"P. herfsi" has been recorded in Czechoslovakia, [ [http://www.ncbi.nlm.nih.gov/sites/entrez?Db=PubMed&Cmd=ShowDetailView&TermToSearch=156143&ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum PubMed - National Institutes of Health] ] Egypt, [ [http://www.ars.usda.gov/is/np/pinkbollworm/pinkbollworm.pdf USDA. A Bibliography of the Pink Bollworm] ] Australia, [ [http://agspsrv34.agric.wa.gov.au/ento/staff4.htm Department of Agriculture and Food, Western Australia] ] northern India, [ [http://www.ias.ac.in/j_archive/currsci/53/1/53-54/viewpage.html Proceedings of the Indian Academy of Science] ] and the United States. It is a regulated pest in Germany. [ [http://www.bba.bund.de/nn_1030794/SharedDocs/07__AG/Publikationen/internat/nz/nz3-seeds-avena-et.pdf,templateId=raw,property=publicationFile.pdf/nz3-seeds-avena-et.pdf Biologische Bundesanstalt für Land- und Forstwirtschaft] ]

Impact on humans

trees.

Humans typically report itching from mite bites within 10 to 16 hours after contact. The victims often do not recall being bitten. The rash that results from the bites is usually described as a red patch with a small blister in the center, most often found on the neck, face, arms, or upper torso. A secondary bacterial infection sometimes arises when the bite is scratched. The suggested treatments include the application of calamine lotion, an antihistamine cream such as Benadryl, or a corticosteroid cream; a suggested preventive measure is the application of DEET before outdoor activity. [ [http://ianrnews.unl.edu/static/0505021.shtml University of Nebraska, 2005 ] ] Anecdotal reports from the Kansas outbreak, however, suggest that DEET might not provide complete protection against "P. herfsi". [ [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5438a3.htm Centers for Disease Control, September 30, 2005] ]

The bites are not life-threatening, but a few individuals suffering 100 or more bites have undergone brief hospitalizations. [ [http://ianrnews.unl.edu/static/0507150.shtml University of Nebraska, July 2005] ]

Footnotes

External links

* [http://mail.pittstate.edu/~dgordon/MysteryBites/MysteryBites.html Photographs of P. Herfsi bites on humans. Pittsburg State University, Pittsburg, Kansas. April 18, 2007]

* [http://www.oznet.ksu.edu/library/entml2/mf2806.pdf Oak Leaf Itch Mite, Alberto Broce, James Kalisch, Kansas State University, October 2007, 2 p., illustrated]